Physiology Part 1 Flashcards
CO=
-CO=SVXHR
What is the Fick principle?
CO=(Rate of O2 Consumption)/(Arterial O2 content-Venous O2 content)
MAP=
- MAP= CO X TPR
- MAP= 2/3 Diastolic P + 1/3 Systolic P
Pulse Pressure=
Pulse Pressure= Systolic P - Diastolic P
-Proportional to SV
SV=
- SV=CO/HR
- SV=EDV-ESV
During the early stages of exercise, CO is maintained by…
Increasing HR and SV
During the late stages of exercise, CO is maintained by…
Increasing HR (SV plateaus)
If HR is too high what happens to CO?
Diastolic filling is incomplete and CO decreases
SV is affected by…
CAP
Contractility, Afterload, Preload
If SV is increased, then CAP…
- Contractility is increased
- Afterload is decreased
- Preload is increased
Factors that increase contractility (and SV)
- Catecholamines
- Increased intracellular Ca
- Decreased extracellular Na
- Digitalis
Factors that decrease contractility (and SV)
- B1 blockade
- Heart Failure
- Acidosis
- Hypoxia/hypercapnea
- Non-dihydropyridine Ca channel blockers
SV increases during…
anxiety, exercise, pregnancy
A failing heart has _____ SV
Decreased
Myocardial O2 demand is increased by
- increased afterload (increased MAP and increased wall tension (from increased heart size))
- Increased contractility
- Increased HR
